A coronary bifurcation is the point at which a side-branch of a coronary artery diverges from a main branch. Approximately 15% to 20% of the 700,000 percutaneous coronary interventions performed in the U.S. during 2010 were for treating stenosis associated with a coronary bifurcation, i.e., a bifurcation lesion. Treating a bifurcation lesion, which is technically challenging, has lower procedural success rates and worse clinical outcomes as compared to treating a non-bifurcation lesion.
Typically, to treat a bifurcation lesion, a stent is implanted in the main branch but not in the side-branch, a so-called provisional approach. More specifically, the stent does not cover the opening of the side-branch, allowing for future treatment of the side-branch if necessary. This approach is taken due to the fact that routine implantation of two stents does not give superior results compared to a single stent. However, the technique frequently leaves the side-branch with significant residual stenosis.
Techniques have been developed that utilize two separate stents to treat bifurcation lesions. A major problem with these techniques is that the site at which the two separate stents overlap can disrupt blood flow and induce thrombus formation. Additionally, the use of a standard non-bioabsorbable stent typically leads to chronic foreign body reactions.
There is a need to develop a dedicated bifurcation stent that can be implanted in both the main and side-branch simultaneously, can physically support the artery walls, can elute drugs into the stenotic area to prevent restenosis, and can biodegrade over time to reduce or eliminate the occurrence of chronic foreign body reactions.